Dual fluid coupling power transmission



Nov. 15, 19,49 A. o. ROBERTS DUAL FLUID COUPLING POWER TRANSMISSION Filed Sept. 20, 1946 2 Sheets-Sheet 1 Z6 3 E a x x L 7 A. o. ROBERTS.

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1949 A. o. ROBERTS DUAL FLUID COUPLING POWER TRANSMISSION 2 Sheets-Sheet 2 Filed Sept. 20, 1946 A. O. ROBERTS.

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ATTORNEYS.

Patented Nov. 15, 194 9 UNITED STAT S PATENT OFFICE DUAL FLUID COUPLING POWER TRANSMISSION Albert 0. Roberts, Dear-born, Micln, assignor to Ford Motor Company, Dear-born, Mich., a corporation of Delaware Application September 20, 1946, Serial No. 698,122

supplying fluid to the fluid coupling n lifli 'which a pressure relief valve is incorporated lto'gfether with means for modulating the action of the pressure relief valve in accordance with engine manifold vacuum. Since. manifold vacuum is 55 of 1 Claim. (CI. 60-54) This invention relates generally to power transproportional to the load, a torque responsive conmissions and has particular reference to power trol is thus provided. 7 I transmissions in which a pair of fluid couplings Other objects and advantages of the invention are utilized. will be made more apparent as this description An object of the present invention is to provide proceeds, particularly when considered in cona power transmission utilizing a pair of fluid nection with the accompanying drawings, in couplings in which one of the fluid couplings 'is which: connected to the driven shaft of the transmission Figure 1 is a longitudinal cross sectional view at one torque ratio and the other fluid coupling through a transmission embodying the present is connected to the driven shaft at another torque 10 invention. 7 ratio through suitable reduction gearing.v Two Figure 2 is a fragmentary longitudinal cross separate power paths are thus provided from the sectional view through a transmission forming a drive shaft to the driven shaft, enabling the engin modification of the invention. torque to be divided and the divided portions i u etisafrasmentary semi-diasrammatical thereof transmitted to the driven shaft at difv w f a portion of the c ntrol mechanism. ferent torque ratios. Preferably one fluid cou- R e g now more particularly to the drawpling is directly connected to the driven shaft n e p w t ssi n shown in Fi ure 1 while the other fluid coupling is connected isvcontsinsd wi h h sin comprising housing through suitable reduction gearing. with t sections H and it. A flywheel I3 is rotatably arrangement, torque multiplication is obtained manned Within the housing and is connected to in only one path As t speed increases t the flange ll of the crankshaft i8 of an internal torque division between the two paths is varied combustion engine (not shown). The reference until finall an of the engine torque is trans character I! indicates a driven or output shaft, mitted through the coupling connected directly] the ward d which is J in the to the driven shaft, power then being transmitted of the flyweel The rearward end of the at a 1 to 1 ratio; driven shaft i1 is Journaled in bearings l8 car- Another object of the invention is to provide fled in the. housing sectlon and is splined at a powertransmission inclu'ding aipair of fluid lg igf connection the pmpener shaft the couplings providing separate powe paths from the drive member to the driven member at difg transmission includes a pair of adjacent ferent torque ratios, in which means are prod couplings A and The impeller; 23 of fluid coupling A is bolted to the rim 24 of the med varying the mid mute! a heel for rotation therewith as a unit The the couplings. The fluid coupling which is diflier 26 of con pling A has an integral web 21 rectly connected to the driven shaft is emptied which is connested by rivets 28 to the flange n at idling speed so that when starting the enof a Sleeve 3| which is splined to the driven tire engine torque is transmitted through the shaft "0 other fluid coupling and the gear reduction to The impeller 32 of mud coupling 3 is identical provide amaximum torque multiplication. Fluid my construction with the impeller ,0! fluid is admitted through a centrifugally operated coupling A but is mounted in the opposite db va 1ve when a predetermined speed has been rection. The back walls of the impellers 23 and tamed and as the coupling is fined an increas' 32 are welded together so that both rotate toing portion of the engine torque is transmitted gethen If desired, the two impellers may be therethlough until finally this coupling trans" formed of one piece, but it is more economical to mits entire engine torque at a 1 t0 1 ratioform separate impellers of sheet metal stampings The other coupling and its reduction s and then to weld the two together. An annular then overr n thr u n o ins clutch cover 33 is bolted to the impeller 32 to form a v still another o e 1' the invention is to closed fluid chamber within which thereismount- P v e a transmission f he ype n i ned ed for relative rotation a runner 34. The runner above which is provided with a fluid p mp for 34 has a web 35 connected by rivets 31 to the flange 38' of a sleeve 39 splined to the hub ll of a sun gear 42. The hub ll is .Iournaled on the driven shaft l1. I

Meshing with the sun gear 42 are a plurality planet pinions 43 iournaled upon shafts 44 carried by the planet carrier 46. The planet carrier 46 has a hub 41 splined to the driven shaft II. Encircling the planet pinions 43 and meshing therewith is a ring gear 48 to which is bolted a ring 49 having an internal bearing surface engageable with the overrunning clutch ii. The overrunning clutch thusconnects the ring gear -18 with tht hub 52 of a reaction member 53 which is bolted to the housing section II.

From the foregoing it will be seen that the runner 26 of fluid coupling A is directly connected to the driven shaft I! while the runner 34 of fluid coupling B is connected to the driven shaft through a planetary gearset and an .overrunning clutch. The planetary gearset provides a reduction, which may be approximately 3 to 1 for automotive use, and the overrunning clutch permits the transmission of power through the planetary gearset in one direction but overruns in the opposite direction of rotation. Thus the planetary gearset provides a torque multiplication, the reaction for which is taken through the over-running clutch and the reaction member 53 to the housing section I l.

A pump housing SI is mounted upon the rearward end of the housing section II and contains a gear pump 56 which is driven by the driven shaft l1 and which supplies fluid under pressure through passages 51 to the central bore 58 of the driven shaft. In addition to supplying lubricating oil to the various bearing surfaces, the pump functions to maintain fluid couplings A and B completely fllled with fluid, communication to the coupling A being through the radial passage 59 in the shaft l1, and communication to the coupling B being through the radial passage 60 in the shaft l1 and the ports Si in the impeller 32.

In operation, it will be seen that the two fluid couplings provide separate power paths at different torque ratios. The path through fluid coupling A can only transmit power at a one to one ratio since the runner 26 is directly connected to the driven shaft, but the path through fluid coupling B and the planetary gearset provides a torque multiplication. When starting, the

engine torque is divided between the two fluid couplings with the result that a torque multiplication is obtained between the drive and driven shafts of the transmission, this resultant torque multiplication being less than the gear ratio of the planetary gearset since a portion of the torque is transmitted through coupling A at a 1 to 1" ratio. Fluid slippage in the couplings A and B compensates for movement between the two power paths.

At higher speeds, a greater portion of the engine torque is transmitted through the path including fluid coupling A, with the result that the overall torque multiplication through the transmission decreases until such time as the the necessary relative formed in the flywheel l3 adjacent the radially inner portion of the torus formed by the fluid coupling. During rotation the fluid in the coupling is thrown radially outwardly by centrifugal force and the coupling remains substantially filled. When the speed drops to idling, however, the centrifugal force is no longer sufllcient to keep the fluid in the torus, and it drains through the holes 66 into the housing section i I and then to the sump (not shown). An annular baiile O5 is mounted upon the flywheel is to direct the fluid away from the flywheel and against the housing section H. The small amount of fluid remaining in the coupling is insufllcient to transmlt any appreciable torque.

Refilling of the coupling A is accomplished through a centrifugally operated valve 68 which has a spring loaded plunger I! normally covering the outlet port H of the radial passage 59 in the driven shaft. When a predetermined rotational speed has been attained the plunger 69 moves outwardly, opening the port 1| and permitting fluid from the pump to enter the coupling A through the outlet port II. It will be noted that with this modification a hello plate I2 is provided upon the impeller 13 to form the sidewall of the fluid chamber formed by the coupling.

In operation this modification secures a higher starting torque since during starting the fluid coupling A is empty and the entire engine torque is transmitted through coupling B and is multiplied through the planetary gearset. As coupling A is filled with fluid it transmits an increasingly greater amount of the engine torque and the resultant torque multiplication of the transmission is accordingdy decreased until sufllcient speed has been attained to cause the overrunning clutch 5| (Figure 1) to overrun the reaction member 53, at which time the entire torque is transmitted through coupling A in direct drive.

Figure 3 illustrates diagrammatically means for controlling the fluid pressure in the system in accordance with the load requirements. The

pressure relief valve 16 limits the output pressure of the fluid pump 11. Movement of the plunger ll of the relief valve is opposed by a spring I! and the operation of the valve is modulated by a vacuum chamber 8| connected to the manifold of the vehicle engine through a conduit 82. The chamber includes a diaphragm O3 -carrying a connecting rod ll. engageable with one end of a lever ll. The lever" is adjustably fulcrumed upon a bracket '1 by a pin and slot connection Land the opposite end of the lever is engageable with the plunger-18 of the valve. It will be seen that with this construction, when the load is light and the manifold vacuum relatively high, the oil presdriven shaft l1 and the planet carrier 46 overrun the overrunning clutch 51. When this occurs,

' no power is transmitted through the path including fluid coupling B, the entire engine torque being transmitted through fluid coupling A at direct drive or 1 to 1 ratio.

Reference is now made to Figure 2 which shows a modification of the construction shown in Figure 1. The general construction of the transmission is the same, except that means are provided for draining the fluid from coupling A during idling and for refilling the coupling when a certain rotational speed has been attained. To accomplish this a series of drain holes 00 are sure in the system will be greater. This greater oil pressure will cause the centrifugally controlled valve 88 to open sooner which will bring the coupling A into operation faster, thus decreasing the torque multiplication. On the other hand, under heavy load conditions when the manifold vacuum is low, the oil pressure in the system will be correspondingly low and opening of the valve II will be delayed, resulting in maintaining a greater we multiplication to accommodate the greater It will be understood that the invention is not to be limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope of the invention. as defined in the appended claim.

said driven shaft and cooperating with said impel lers to. form separate fluid circuits, means for transmitting power from said runners to said driven member at different torque ratios, 9. fluid pump driven by said driven member, a conduit leading from the outlet of said fluid pump axially through said driven member, a passage establishing communication between said conduit and one of said fluid couplings to maintain the latter substantially filled with fluid under pressure, a supporting member'forming a hub for the runner of the other of said fluid couplings, a radial passage in said supporting member communicating at its inner end with said conduit and at its outer end with a port opening into said last mentioned fluid coupling," a radially extending slidable plunger having aportion adapted to selectively cover and uncover said port, a spring normally urging said plunger radially inwardly to a position covering said port, said plunger being moved radially outwardly by centrifugal force against the action of said spring when a predetermined speed is reached by the runner of said last mentioned coupling to admit fluid from said conduit 6 to said last mentioned coupling to progressively decrease the resultant torque multiplication of thefltransmission as said last mentioned coupling is fllled with fluid, and an axially extending outlet passage leading i'rom said second mentioned fluid coupling at a point so located as to drain a substantial portion of the fluid from said second mentioned coupling when the latter is idling or stationary.

ALBERT O. ROBERTS.

REFERENCES crrEn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,015,300 Dell et al Sept. 24, 1935 2,018,616 Martyrer et al Oct. 22, 1935 2,077,580 Patterson Apr. 20, 1937 2,150,151 Burrows et a1 Mar. 14, 1939 2,203,177 Patterson June 4,1940 2,324,733 Smirl July '20, 1943 2 ,341,624 Kieser Feb. 15, 1944 2,354,393 Miller July 25, 1944 FOREIGN PATENTS Number Country Date 407,146 Great Britain Mar. 15, 1934 427,956 Great Britain May 2, 1935 365,474 Italy Dec. 5, 1938 

